I use an external 4k monitor set as my main display with scale set at 100%, the 4K display on my laptop is set at 200% scale. Windows-shift-s screen snip does not allow me to capture on the external monitor. I have to set the scale on both displays to the same setting for snipping to work. Also some applications on the external monitor (100%) display using the scaling from the laptop monitor (200%). Finally, the taskbar on the laptop monitor (200%) displays using the external scaling (100%) and is too small to be usable.